The Characteristics of Working Overtime and Their Associations with Nurse and Patient Outcomes: A Systematic Review of Observational Studies

To fill the nursing shortage, and to ensure continuous 24 h nursing coverage, working overtime has been increasing steadily over the recent years. Although working overtime has been associated with adverse nurse and patient outcomes, the results of existing studies remain scattered. This study aimed to systematically synthetize existing evidence on the characteristics of working overtime (i.e., mandatory or voluntary) and their associations with nurse and patient outcomes. Method: A systematic review was conducted. MEDLINE, CINHAL, Scopus, Campbell, Cochrane Library and PsycINFO were examined from March 2014 to April 2025. Two reviewers independently selected studies and extracted relevant data using a standardized extraction grid. Results: Among 5827 retrieved articles, 71 studies (65 cross-sectional and six longitudinal) met our inclusion criteria. These studies examined 27 adverse nurse outcomes and 10 adverse patient outcomes. Mandatory overtime was associated with eight adverse nurse outcomes, and no beneficial nurse outcomes. Voluntary overtime was associated with three adverse nurse outcomes. We found no study examining the association between mandatory/voluntary OT and patient outcomes. No study showed beneficial impacts of overtime on patient outcomes. Unspecified OT was inconsistently associated with adverse nurse (eg., burnout, sleep disorder) and patient outcomes (e.g., poor quality of care). Conclusion: While evidence suggests that working overtime is associated with numerous adverse nurse and patient outcomes, existing results are inconsistent. Robust research methods and longitudinal designs are required to better ascertain these associations. Stratifying the analyses by the type of exposure (i.e., voluntary vs. mandatory overtime), may also be beneficial.